Hi Tim
Thank you for getting in touch. Here is the 3.21 changelog:
3.21 :- 2020-04-07 :- Medium priority
* Dropped call to deprecated function wpgmaps_filter
* Fixed only one category assigned to submitted markers when multiple categories have been selected by the user
* Fixed custom field data not being submitted
We’ve updated the “tested up to” string on our update server as well, thank you for pointing that out.
Is there anything else we can help you with?
Kind regards
– Perry